The invention relates to digital tape drive storage devices, and in particular, to a sensing assembly for determining the connection status between magnetic tape within the tape cartridge and a takeup reel within a digital tape drive.
Digital data is stored on tape drives utilizing a variety of designs, but in all cases, magnetic tape media is wound between a pair of tape reels as data is transferred to or from the tape media. In the art of data storage, the physical space required to store data is an important concern. To conserve space, tape drives often use a single reel tape cartridge design, which utilizes a supply reel located within the tape cartridge and a takeup reel located within the tape drive. After the tape cartridge is inserted into the tape drive, the magnetic tape must be connected to the takeup reel. Various methods have been employed to make this connection. One such method connects the magnetic tape to the takeup reel via a buckle between a tape cartridge leader and a takeup leader as described in U.S. Pat. No. 4,572,460.
The magnetic tape within the tape cartridge is terminated at one end by the tape cartridge leader, which is a strong flexible plastic strip containing an ovular aperture on its distal end. The takeup leader is a similar strong flexible plastic strip attached at one end to the takeup reel. The other end has a stem and tab designed to buckle with the ovular aperture on the tape cartridge leader. When the tape cartridge is inserted into the tape drive, the takeup leader and tape cartridge leader are positioned to buckle together. This system improved on prior art systems employing a combination of vacuum and air pressure to guide the tape through a path, but still results in connection failures due to wear, misalignment or other causes.
When the tape cartridge is ejected, first the two leaders should become separated or disconnected to allow the tape cartridge to be removed from the tape drive. When the tape cartridge is ejected while the two leaders are still connected, damage can occur to both leaders, rendering the tape drive inoperable and the tape cartridge damaged. In the prior art, disconnect failures were not always detected by the tape drive. Due to the nature of the tape media, once the tape media within the tape drive is damaged, the data previously recorded on the tape media is not recoverable. In addition, because the disconnection mechanism wears out overtime, the problem of disconnection failures is most common in high duty cycle applications, where it causes the most damage. For example, in applications such as library tape drive systems, a broken tape results in an eject failure. The library is then inoperable since one of the tape cartridge leaders failed to disconnect from the takeup leader.
A sensing assembly for use in determining if magnetic tape within the single reel tape cartridge properly connects to the take up reel within the tape drive during loading of the tape cartridge is disclosed by Zweighaft (U.S. Pat. No. 6,186,430). The sensing apparatus disclosed in ""430, in conjunction with a processor detects various movements in the tape drive consistent with specific connection statuses, namely, proper connection and connection failure. Detecting movement first of the freely rotating supply reel and then the takeup reel as the supply reel is slightly energizes provides confirmation that the connection exists.
While the apparatus in ""430 detects connection status when the tape cartridge is inserted into the tape drive, the apparatus does not detect a failure during disconnection of the takeup leader from the tape cartridge leader when a tape cartridge is ejected from the tape drive. Failure of the takeup leader and the tape cartridge leader to disconnect when the tape cartridge is ejected from the tape drive results in damage to the takeup leader and the tape media within the tape cartridge. Once the tape media within the tape cartridge is damaged, the data previously stored on the tape media can not be recovered.
For these reasons, it is desirable to have a sensing mechanism that detects a failure of the takeup leader to disconnect from a tape cartridge leader and alerts an operator of the disconnection failure.
The present tape drive sensing assembly overcomes the problems outlined above and advances the art by providing an apparatus and method for testing the disconnection status of the tape cartridge leader from the takeup leader prior to removal of the tape cartridge from the tape drive. A sensing assembly provides a means for notifying an operator when the takeup leader and tape cartridge leader fail to properly disconnect.
The sensing assembly detects the position of the takeup leader following a disconnection operation to determine the successfulness of the unbuckle operation. If the disconnection operation fails to disconnect the tape cartridge leader from the takeup leader, the sensing assembly generates a signal that can be used to inform the operator of the disconnection failure.